Over the summer I've been playing with DSP, and ended up with multiple set-ups. One has to go. At this one of the most "plug and play" I think it's the best one to offer up.
OpenDRC-DI (https://www.minidsp.com/products/opendrc-series/opendrc-di)
This takes a digital input (coax, optical or AES)
It applies one of four filters - more on that in a moment
It then outputs digital (same options) to your DAC
UMIK-1 (https://www.minidsp.com/products/acoustic-measurem